This invention relates in general to drives operated with continuous strips and in particular to a new and useful strip drive for advancing materials for processing.
The invention relates particularly to an apparatus for treating strips of metal, plastics, paper or the like with a strip drive and a strip store being disposed at the apparatus entry and apparatus exit. A processing section is disposed between the two stores and a strip drive is disposed after each section. The strip stores comprises a horizontally movable loop trolley or a roll table movable vertically in a loop tower.
A strip store for bridging pauses during the changing of coils or windings or reels must be provided at the entry and exit of apparatus for heating strips, for example, of metal, plastics, paper and foils. The processing section for treating metal strips may be a rolling mill or a stretching apparatus or a pickling bath or a heat treatment facility or a galvanizing plant or color coating plant or the like. Horizontal and vertical strip stores are known. Horizontal strip stores usually have two loop trolleys, each of which have an independent tension-controlled drive. Each trolley drive is connected to the associated loop trolley by way of a cable and has the sole function of keeping the set-up strip tension very constant during filling and emptying of the store in order to obviate irregular strip treatment and, therefore, impairments of quality. The drives for the loop trolleys used in the treatment of metal strips are designed for cable tensions of from 10 to 30 tons and require elaborate control facilities for the cable tensions. It must also be possible to maintain cable tension during prolonged stoppage times of the trolleys. This requirement calls, for example, for the use of special electric motors having heat exchangers or dual drives. Trolley drives of this kind are very expensive and their installation and servicing are complex. Similar considerations apply to the space they require and to repair work on them. Circumstances are similar for vertical strip stores which are of use more particularly for storing long lengths of strip. The vertical type has a stationary roll carrier and a vertically movable roll table. Associated therewith is a table drive which moves the table up or down with a tension adjustable to suit the required strip tension.